We plan to extend and expand our horizontal studies of postoperative (p.o.) in vivo and in vitro cell-mediated immunity (CMI) of breast cancer (BCa) patients to autologous tissues with particular reference to their prognostic significance. Special attention will be paid to the p.o. interval at which such reactivity is demonstrable and to the p.o. duration of such reactivity. Simultaneous in vitro measurements will also be performed against RIII-gp55 at various concentrations. During the coming year we shall furthermore investigate the skin test reactivity of BCa patients to highly purified gp55. The immunological data will be correlated with clinical data and with prognostically significant BCa tissue characteristics, including estrogen/progesterone receptor levels. BCa tissues from immunologically characterized patients will be analysed physico-chemically and immunologically in an attempt to identify and isolate the immunogen(s). In view of the apparent prognostic significance of CMI to autologous BCa we shall attempt to identify the nature of the reactive cell populations found on positive skin windows, by means of immunocytochemical characterization (PAP technique, utilizing monoclonal antibodies against T-lymphocyte subclasses). We shall also test the ability of putative immunomodulators to restore or enhance in vitro the reactivity of leukocytes to autologous BCa tissue and gp55. Furthermore, we shall expand our studies of CMI to gp55 and selected BCa tissues among risk-defined control women, including patients with benign breast diseases.